Auto-Injector Comprising a Resettable Releasing Safety Device

ABSTRACT

An autoinjector including a housing, a receptacle for an active substance, which receptacle, together with a connected injection needle, is displaceable within the housing by spring force for inserting the injection needle into a patient, a piston displaceable within the receptacle by spring force for expelling the active substance, a transfer mechanism for transferring the spring force to the receptacle and/or to the piston, a holding mechanism for holding the transfer mechanism, a releasing mechanism for causing the holding mechanism to release the transfer mechanism when the releasing mechanism is moved from a first position into a second position, and a resetting mechanism for moving the releasing mechanism from the first position into the second position without during the move causing the transfer mechanism to be released.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/132,715, filed on Mar. 19, 2005, which is continuation ofInternational Patent Application No. PCT/CH2003/000758, filed on Nov.17, 2003, which claims priority to Swiss Application No. 1987/02, filedon Nov. 25, 2002, the contents of which are hereby incorperate byreference in their entirety.

BACKGROUND

The present invention relates to devices and methods of dispensing,administering, injecting or delivering substances. More particularly, itrelates to devices and methods for making injections, includingautoinjectors for the automatic injection of an active substance, suchas medicinal substances, insulin, etc.

Typically, such autoinjectors have a receptacle for the activesubstance, which receptacle, together with a connected injection needle,is displaceable within a housing by spring force for the purpose ofinserting the injection needle. Such autoinjectors typically have asyringe piston, which, for the purpose of expelling the activesubstance, is displaceable within the receptacle through spring force,transfer means that transfer the spring force to the receptacle and/orto the syringe piston, holding means for holding the transfer means, andreleasing means for causing the holding means to release the transfermeans when the releasing means are brought from a first position into asecond position.

Autoinjectors of the type mentioned above are known in many embodiments.One use they serve is for the self-administration of medication by apatient. Many of the known autoinjectors include a releasing safetydevice, which is intended to prevent an injection procedure from beinginadvertently triggered. These releasing safety devices are, in mostcases, components that block the releasing means from being activated.These components may be, for example, formed as slides that are movablein relation to the releasing means or as covers or stoppers that are tobe removed prior to the injection. These additional components obviouslyincrease the production costs of autoinjectors, as well as complicatetheir use.

SUMMARY

Objects of the present invention include to provide an autoinjector inwhich the releasing means does not require additional operatingelements, and to provide an autoinjector that can be unlocked and lockedagain without triggering an injection.

According to the present invention, this is achieved by providing anactuable resetting means which make it possible to bring a releasingmeans from a first position into a second position without, in theprocess, causing a transfer means to become unblocked.

In one embodiment of the present invention, the unlocking takes placethrough the bringing of the releasing means from the second positioninto the first position. Starting from this first position, an injectioncan now be triggered through the bringing of the releasing means intothe second position. On the other hand, however, through actuation ofthe resetting means, the releasing means can be brought again from thefirst position back into the second position without the triggering ofan injection. An autoinjector according to the present invention hasrelatively few components and is simple and reliable in its operation.

In one embodiment, the present invention comprises an autoinjectorcomprising a housing, a receptacle for an active substance, whichreceptacle, together with a connected injection needle, is displaceablewithin the housing by spring force for inserting the injection needleinto a patient, a piston displaceable within the receptacle by springforce for expelling the active substance, a transfer mechanism fortransferring the spring force to the receptacle and/or to the piston, aholding mechanism for holding the transfer mechanism, a releasingmechanism for causing the holding mechanism to release the transfermechanism when the releasing mechanism is moved from a first positioninto a second position, and a resetting mechanism for moving thereleasing mechanism from the first position into the second positionwithout during the move causing the transfer mechanism to be released.

In one embodiment, the present invention comprises an injection devicecomprising a syringe which can be displaced within a housing by means ofthe power exercised by springs. Transducing means transduce said springpower to the syringe while resilient stopping cams which engage into agroove of the transducing means maintain the transducing means in theinitial position thereof until being released. In order to prepare aninjection, an axially displaced releasing head is pulled back from afirst position into a second position in which the safety device of theautoinjector is released. In order to trigger an injection, thereleasing head is moved forward, resilient tongues that are disposed onthe releasing head engaging with the stopping cams so as to push saidstopping cams apart. Resetting buttons which are disposed inside thereleasing head act upon the resilient tongues when being pressed suchthat the resilient tongues do not engage with the stopping cams when thereleasing head is moved forward.

In one embodiment of an autoinjector in accordance with the presentinvention, holding means are designed as elastic nubs that engage withtheir free ends a recess that is provided on a transfer means. Releasingmeans comprise elastic tongues that act on the elastic nubs and bringthe latter out of their engagement in the recess, when the releasingmeans are moved from a first into a second position. These measures makepossible a simple design, and the elastic nubs and the elastic tonguescan be produced as plastic parts in the injection-molding process. Itthereby becomes possible, according to a further embodiment of theinvention, to so design the resetting means that through their actuationthe elastic tongues become elastically deformed in such a way that thetongues do not act on the elastic nubs when the releasing means arebrought from the first into the second position.

According to one preferred embodiment of the present invention, thereleasing means display a releasing head that is axially displaceable inrelation to the housing. This makes possible operation of anautoinjector using only one hand. If the releasing head in its firstposition is further back than in its second position, then it can bepushed forward for the releasing, which promotes the correct positioningof the autoinjector on the skin of the patient. If, in addition, thereleasing head is arranged at the rear end of the housing, i.e., the endopposite to the injection needle, then the actuation of the releasinghead is further facilitated, because in order to trigger the injectionthe user can then either take hold of the periphery of the actuationhead or press on its rear face.

Spring means that prestress the releasing head in the direction of itssecond position are provided according to a further embodiment of theinvention. This promotes not only the releasing or the resetting intothe locked position, but also ensures that the releasing means remainsin the second position after the injection. Advantageously, theresetting means display at least one push-button that is accommodated inthe releasing head and is actuable in a direction generally radial tothe longitudinal axis of the autoinjector. Thus, with a depressedpush-button the releasing head can be guided from the first into thesecond, locked position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal section through an embodiment of anautoinjector according to the present invention, in a loaded state;

FIG. 2 is a longitudinal section through the autoinjector of FIG. 1 inan unlocked state, the sectional plane being rotated 90° in relation toFIG. 1;

FIG. 3 is a longitudinal section through the autoinjector of FIG. 1after the insertion of the injection needle, the section being madethrough the same plane as in FIG. 2;

FIG. 4 is a longitudinal section through the rear part of theautoinjector in the same operating position as in FIG. 3, the sectionbeing made through the same plane as in FIG. 1; and

FIG. 5 is a cross section along the line V-V of FIG. 4, in enlargedscale in relation to FIG. 4.

DETAILED DESCRIPTION OF THE DRAWINGS

An autoinjector in accordance with the present invention comprises oftwo main components, namely the reservoir part, shown on the left inFIGS. 1 through 3, in which a filled syringe 50 is accommodated, and thepower pack, shown on the right in the same drawings, in which aresituated the parts serving the insertion and expelling of the syringe50. The two main components are detachably connected to each otherthrough a bayonet-type connection between a receiving sleeve 16 and apower sleeve 1. In the following description, the end of theautoinjector at which the injection needle is located is referred to asthe front.

With reference to FIG. 1, which shows the operationally-readyautoinjector, the power pack will be described first. The parts for thedriving of the autoinjector are accommodated in the grip sleeve 14, tothe rear end of which is attached an indicator window 51. The indicatorwindow 51 is produced of transparent or translucent material or hasopenings, for example in the form of slots, which allow the observationfrom the outside of the indicator 12 that is displaceably accommodatedin the indicator window 51. The indicator 12 is preferably formed in aring-shaped manner and is thereby visible from any direction around theautoinjector. Arranged at the rear end of the autoinjector is theactuation head 13, which on its rear face is provided with a cover disc15. Housed within the grip sleeve 14 is the power sleeve 1. At its rearend, the power sleeve 1 is connected to a catch sleeve 8 by means of asnap connection. The catch sleeve 8 displaceably accommodates in itsinterior a spring sleeve 10. The spring sleeve 10 is coupled at the rearto the indicator 12 by means of a snap connection. At the front side ofthe spring sleeve 10, the transfer part 5 is displaceably supported inthe power sleeve 1. The transfer part 5 has the task of actuating thepiston 52 of the syringe 50, in order to expel the contents of thesyringe, as will be described in greater detail later. Accommodatedinside the spring sleeve 10 is a spring 9 in the stressed state, whichspring is supported in the front on the spring sleeve 10 and in the rearpresses against the catch sleeve 8. A second spring 11, likewise in thestressed state, is located on the outside of the spring sleeve 10 and issupported in the front on the transfer part 5 and in the rear pressesagainst the spring sleeve 10.

A piston guide 4 rests with its front, sleeve-shaped end against theshoulder of the syringe and extends through the transfer part 5, thespring sleeve 10, and the catch sleeve 8 into the region of theactuation head 13. The piston guide 4 is prestressed forward by a spring7, which at the rear, rests on the catch sleeve 8. At its rear end thepiston guide 4 is held in the position shown in FIG. 1 by means of twostopping nubs 31 formed on the catch sleeve 8, which nubs engage agroove 32 formed at the rear end of the piston guide 4. Catch members,for example balls 6, which are taken up in radial openings 33 of thepiston guide 4 and engage recesses 34 in the transfer part 5, ensure inthis operating position that the transfer part 5 and the piston guide 4can only move in common. Of course, the catch members could have anysuitable shape, for example that of pins.

A description of the reservoir part now follows. The parts for theaccommodation of the syringe 50 are, as mentioned, housed in thereceiving sleeve 16, which, as described, can be connected to the powersleeve 1. A sliding sleeve 21 accommodates within itself the syringe,with the interposition of a needle holder 22. In the case of luer slipconnections, the needle holder 22 ensures that the injection needle 37cannot be removed from the syringe so long as the latter is situated inthe autoinjector. At the front, the needle holder 22 lies against asupport ring 24 connected to the sliding sleeve 21. In the case ofsyringes and needle having luer lock couplings, in which therefore theinjection needle is connected to the syringe by means of a thread, noneedle holder 22 is present. The sliding sleeve 21 is displaceablewithin the receiving sleeve 16 and is pushed by a spring 20 into theoperating position shown in FIG. 1. A sleeve-shaped needle protector 17is displaceable within the receiving sleeve 16. The needle protector 17is closed at the front by a snap cover 23, which leaves open a passagefor the injection needle, and at its rear end has an inward-pointingflange 35. A spring 18 rests at the front against the snap cover 23 andat the rear against a carrier ring 19. In this figure, the spring 18 isin its relaxed state.

In preparation for the injection, the autoinjector must be brought fromthe locked state shown in FIG. 1 into the unlocked state, as representedin FIG. 2. For this purpose, the actuation head 13 is moved rearward.This can take place in that the apparatus is grasped with one hand onthe receiving sleeve 16 and with the other hand on the actuation head13, and the two parts are pulled apart. However, by virtue of the designand arrangement of the actuation head 13, it is also possible to hold onto the auto injector at the grip sleeve 14 and, with the thumb of thesame hand, to push the actuation head 13 rearward. Circumferential ribsprovided on the actuation head 13 can prevent a slipping of the thumb.This rearward pushing of the actuation head 13 is referred to as theunlocking movement in the following. In the unlocking movement, a regionof the indicator window 51 at the front edge of the actuation knob 13 isopened, on the inside of which window a conspicuously-colored (e.g.,red) warning sleeve 53 becomes visible, which indicates clearly that theautoinjector is now unlocked and ready for the injection. During theunlocking movement, tongues 36, which are formed at the inside on thecover disc 15 of the actuation head 13, are displaced by the stoppingnubs 31 formed on the catch sleeve. The tongues and the stopping nubsare shaped such that in the unlocking movement the tongues 36 give wayradially in an elastic manner while they slide over the ends of thestopping nubs 31, which hold on to the piston guide 4 by engaging thementioned groove 32. After the unlocking movement, the tongues 36 formedon the actuation head 13 act as wedges between the stopping nubs 31. Theshape of the tongues 36 can be seen especially clearly in FIG. 4. Theunlocking movement causes the stressing of a spring 3, which actsbetween hooks formed on the catch sleeve 8 and a retaining part 60fastened in the actuating head by a snap connection, thus pushing theactuation head into its initial position according to FIG. 1 and thusensuring that the tongues 36 rest against the stopping nubs 31 with aslight prestress. The autoinjector is now ready for the injection and ispositioned with the snap cover 23 at the desired location on the skin ofthe patient. The patient holds on to the autoinjector at the grip sleeve14. To trigger the injection, only a pushing forward of the actuationhead 13, i.e., in the direction of the body of the patient, must now becarried out.

In the triggering movement, the tongues 36 press between the stoppingnubs 31 and spread these radially apart, whereby the piston guide 4 isreleased and thrust forward by the force of the spring 7. The insertionis also supported by the force of the springs 9 and 11, which act on thetransfer part 5. Since the transfer part 5 is connected to the pistonguide 4 via the balls 6, there exists a spring system, consisting of thesprings 7, 9, and 11, having a relatively high initial force, whichcontributes to the reliable pushing forward of the injection needle tothe full penetration depth. The force of the springs is transferred viathe slotted, sleeve-shaped front end 4′ of the piston guide 4 to theshoulder of the syringe 50 and pushes the syringe forward, together withthe sliding sleeve 21 in which the syringe is accommodated, so that theinjection needle 37 is pushed forward and penetrates the skin of thepatient. In this movement, the sliding sleeve 21 compresses both thespring 20 and—via the carrier ring 19—the spring 18. The insertionstroke is limited by the abutting of the shoulder 40 of the piston guide4 against an inner step 41 of the power sleeve 1. In this end position,the openings 33 in the piston guide 4, which openings accept the balls6, are aligned with recesses 42 provided in the power sleeve 1, theballs 6 can give way to the outside, and the coupling between the pistonguide 4 and the transfer part 5 is abolished. Simultaneously, the pistonguide 4 is now locked against the power sleeve 1, so that the force ofthe spring 20 is taken up by the power sleeve and consequently does notact against the force of the spring 7. Thus, the injection can nowautomatically begin, in that the piston 52 of the syringe is thrustforward further by the transfer part 5 under the force of the springs 11and 9. Simultaneously with the insertion motion, the spring 18 isstressed by the carrier ring 19, which is moved by the sliding sleeve 21in a leftward direction in the drawings.

FIG. 3 shows the autoinjector in the operating state just described. Theneedle 37 is fully extended, while the medication is still located inthe syringe 50. Starting from the operating state shown in FIG. 3, theexpelling of the medication now takes place automatically. The balls 6release the transfer means 5 in such a way that the transfer means canmove into the piston guide 4 and in the process can actuate the piston52 of the syringe. Through the gradual relaxing of the springs 11 and 9,the spring sleeve 10, and with it the indicator 12, is shifted forward,so that the indicator 12 reaches its end position when the piston 52 isall the way forward in the syringe 50 and, consequently, all of theliquid present in the syringe has been expelled. As a result, the useris able to follow the course of the injection process and sees, with theaid of the indicator 12, that the entire contents of the syringe hasbeen expelled. The distance that the indicator 12 covers is independentof the stroke of the piston 52 of the syringe and can be substantiallyshorter than the stroke of the transfer part 5. Through this means, onthe one hand an unnecessary long autoinjector is avoided, and on theother hand, syringes with different strokes can be used with the sameautoinjector. This structure also has the additional advantage that therelatively high initial force of the springs 9 and 11 is used for theinsertion process and, subsequently, the relatively low ending force isutilized for the injection process, which therefore takes place moreslowly, as is desirable.

Elastic tongues 38 provided in the sliding sleeve 21 are, at thebeginning of the insertion stroke, prevented from protruding outward bya circumferential, inward-projecting step 39 of the receiving sleeve 16.At the end of the insertion stroke, the elastic tongues protrude beyondthe jacket surface of the sliding sleeve 21. After the indicator 12 hassignaled the complete expelling of the medication, the user can withdrawthe autoinjector. The spring 18, which had been prestressed during theinsertion process, ensures that the needle protector 17 remains incontact with the skin of the patient during the withdrawal of theautoinjector. Thus, the needle protector 17 shifts forward in relationto the receiving sleeve 16 until it completely covers the injectionneedle 37. The elastic tongues 38 snap outward behind the flange 35 ofthe needle protector 17 and ensure that the latter cannot be pushed backinto the receiving sleeve 16. Any risk of an unintentional injury by theinjection needle is thereby substantially eliminated.

The situation may arise in which a user does not wish to carry out aninjection after having unlocked the autoinjector, whether it be becausehe flinches from doing it or because he is disturbed. It would be verydangerous to simply lay aside the autoinjector in the unlocked state.Thus, in the autoinjector according to the invention means are providedthat allow the unlocked autoinjector to be brought back again into thelocked state without triggering the injection. These means includeresetting buttons 62 having a tapered region 63, which buttons projectradially through the releasing head 13 from opposite sides and extendbetween the tongues 36, as can be seen clearly in FIG. 5. If theseresetting buttons 62 are pressed, their wedge-shaped regions 63 movebetween the tongues 36 and spread these apart. Now the releasing head 13can be pushed back again from the position shown in FIG. 2 into theposition shown in FIG. 1, without a triggering of an injection takingplace. This resetting movement, in which the spread tongues slide overthe stopping nubs 31 without pressing the latter, is supported by theforce of the spring 3. The resetting buttons are guided in the releasinghead 13 in a radially-sliding manner. An elastic ring 64, which reacheswith pins 65 into corresponding bores in the resetting buttons 62, holdsthe resetting buttons 62 in position, as is especially clear in FIG. 5.Simultaneously, this elastic ring 64 serves as a restoring spring inorder to restore the resetting buttons 62 to their initial positionafter the pressing, as is shown in FIG. 5. Upon actuation of theresetting buttons 62 the elastic ring 64 is deformed from the showncircular shape into an elliptical shape. In principle, the task of theresetting could also be achieved by a single restoring resetting button,which is this case would be symmetrically tapered, so that uponactuation it would be pushed between the tongues 36 in the manner of awedge. However, in some embodiments, two resetting buttons 62 areergonomically preferable, since these can be compressed, for example,with the thumb and index finger, whereupon the releasing head 13 revertsto the locked position through the force of the spring 3.

While various embodiments, including preferred embodiments, of thepresent invention have been described herein, it is contemplated thatvarious modifications could be made without deviating from the spirit ofthe present invention. Accordingly, it is intended that the scope of thepresent invention be dictated by the appended claims.

1. An autoinjector comprising: a housing; a receptacle for an activesubstance, which receptacle, together with a connected injection needle,is displaceable within the housing by spring force for inserting theinjection needle into a patient; a piston displaceable within thereceptacle by spring force for expelling the active substance; atransfer mechanism for transferring the spring force to at least one ofthe receptacle and piston; a holding mechanism for holding the transfermechanism; a releasing mechanism for causing the holding mechanism torelease the transfer mechanism when the releasing mechanism is movedfrom a first position into a second position; and a resetting mechanismfor moving the releasing mechanism from the first position into thesecond position without during the move causing the transfer mechanismto be released.
 2. An autoinjector for the automatic injection of anactive substance, said autoinjector comprising a receptacle for theactive substance, which receptacle, together with a connected injectionneedle, is displaceable within a housing by spring force for the purposeof inserting the injection needle, a syringe piston, which for thepurpose of expelling the active substance is displaceable within thereceptacle by spring force, a transfer means that transfer the springforce to at least one of the receptacle and syringe piston, a holdingmeans for holding the transfer means, a releasing means for causing theholding means to release the transfer means when the releasing means arebrought from a first position into a second position, and selectivelyactuable resetting means to bring the releasing means from the firstposition into the second position without causing the transfer means tobe released.
 3. The autoinjector according to claim 2, wherein theholding means comprises elastic nubs that with their free ends engage arecess provided on the transfer means.
 4. The autoinjector according toclaim 3, wherein the releasing means comprises elastic tongues that acton the elastic nubs and bring the nubs out of engagement in the recesswhen the releasing means are moved from the first into the secondposition.
 5. The autoinjector according to claim 4, wherein actuatingthe resetting means causes the elastic tongues to elastically deform sothe tongues do not act on the elastic nubs when the releasing means arebrought the first into the second position.
 6. The autoinjectoraccording to claim 5, wherein the releasing means comprise a releasinghead axially displaceable in relation to the housing.
 7. Theautoinjector according to claim 6, wherein the releasing head in itsfirst position is further rearward in relation to the housing than inits second position.
 8. The autoinjector according to claim 7, whereinthe releasing head is adjacent to the rear end of the housing, whichrear end is opposite to the injection needle.
 9. The autoinjectoraccording to claim 2, further comprising spring means for urging thereleasing head in the direction of its second position.
 10. Theautoinjector according to claim 9, wherein the resetting means comprisesat least one pushbutton accommodated in the releasing head and actuablegenerally radially with respect to a longitudinal axis of theautoinjector.
 11. An autoinjector, comprising: a housing for enclosing areservoir, an injection needle fluidly coupled to the reservoir, and apiston for displacing fluid in the reservoir though the injection needleto deliver a dose to a patient; a transfer mechanism for applying atransferring force to the piston in a dose delivery direction, whereinthe transfer mechanism is spring-loaded; a gripping mechanism that gripsthe transfer mechanism to prevent movement of the transfer mechanismprior to applying the transferring force to the piston; a triggermechanism for triggering operation of the transfer mechanism, therebydelivering the dose to the patient; a release mechanism coupled to thetrigger mechanism, wherein the release mechanism is enabled by movingthe trigger mechanism in a direction substantially opposite to the dosedelivery direction from a first position into a second position, andwherein the release mechanism releases the gripping mechanism when thetrigger mechanism is moved from the second position to the firstposition, thereby delivering the dose to the patient; and a resettingmechanism coupled to the trigger mechanism for disengaging the releasemechanism when the trigger mechanism is in the second position prior todelivery of the dose to enable the trigger mechanism to return to thefirst position without releasing the gripping mechanism.
 12. Theautoinjector of claim 11, wherein the gripping mechanism compriseselastic nubs that engage grooves in the transfer mechanism.
 13. Theautoinjector of claim 12, wherein the release mechanism comprises awedge-shaped elastic tongue that releases the elastic nubs of thegripping mechanism by sliding between the nubs to disengage the nubsfrom the grooves in the transfer mechanism when the trigger mechanism ismoved from the second position to the first position, thereby enablingthe transfer mechanism to apply spring-loaded force to the piston. 14.The autoinjector of claim 13, wherein the resetting mechanism comprisesa tab that separates the wedge-shaped elastic tongue from the nubs toenable the wedge-shaped elastic tongue to slide past the nubs withoutdisengaging the nubs from the grooves of the transfer mechanism when thetrigger mechanism is moved from the second position to the firstposition.